Intermediate fragment of aPKC inhibitor compound, its preparation method and application

Abstract

The present invention relates to an intermediate fragment of an aPKC inhibitor compound, its preparation method and uses. Specifically, the compound of the present invention has the structure of general formula I; wherein, R 2 is selected from one or more of Boc, Bn, Cbz, PMB, SEM, Cbz, Ts, Bz, F-moc and Ac, and R 3 is selected from —C(=O)OH, —C(=O)NH2 or —CN. The present invention also discloses the preparation method of the compound and the method for further reacting to obtain 2-piperazineacetonitrile and its pharmaceutically acceptable salts, etc., which has the advantages of using cheap raw materials, avoiding flammable, explosive and highly toxic reagents, and being suitable for industrial scale-up. The present invention is beneficial to promoting the development of atypical protein kinase C inhibitors. General formula I

Description

Technical Field

[0001] The present invention belongs to the field of pharmaceuticals, and particularly relates to an intermediate fragment of an aPKC inhibitor compound, a preparation method thereof, and an application thereof. Background Art

[0002] Atypical protein kinase C (aPKC) is a subfamily in the protein kinase C (PKC) family, and has structural features and functional characteristics different from other subtypes in the PKC family. aPKC plays an important regulatory role in regulating various biological events such as the establishment of cell polarity, the dynamic assembly of the cytoskeleton, the asymmetric division of cells, and vesicle trafficking, thus widely affecting the development of various tissues and organs and the occurrence and development of various diseases. aPKC includes atypical protein kinase Cι (PKC-iota, PKCι) and atypical protein kinase Cζ (PKC-zeta, PKCζ). PKCι is a known oncogene in non-small cell lung cancer (NSCLC). PKCζ removes the pro-apoptotic function of Bax through phosphorylation, and its activity is related to the resistance to various cytotoxic agents and genotoxic agents, and can be used as a target for chemosensitization of tumor cells. Therefore, aPKC inhibitors are expected to become blockbuster drugs in tumor treatment.

[0003] Currently discovered aPKC inhibitors include azaindazole inhibitors. 2-Piperazineacetonitrile has attracted much attention as an important intermediate for the production of such inhibitors. However, there are many problems in the current preparation method of 2-piperazineacetonitrile.

[0004] For example, the following technical route is adopted in patent WO2014052699 for preparation:

[0005]

[0006] The problems it has are:

[0007] 1. The compounds represented by chemical formula 5 and chemical formula 6 of the raw materials are expensive;

[0008] 2. Lithium aluminum hydride (LiAlH4) is used in step A2, which has certain risks and is not suitable for industrial scale-up;

[0009] 3. Potassium cyanide (KCN) or sodium cyanide (NaCN), highly toxic substances, are used in step A4;

[0010] 4. Palladium-carbon hydrogen gas (Pd / H2) is used in step A5 to remove the benzyl group. Palladium-carbon is expensive and not suitable for industrial scale-up.

[0011] Again, for example, the following technical route is adopted in patent CN112694475A for preparation:

[0012]

[0013] The existing problems are as follows:

[0014] 1. The compound (allyl cyanide) represented by Chemical Formula 7 in Step B1 is a highly toxic substance and is expensive. The reaction uses bromine (Br2), which is a highly corrosive reagent and is not suitable for industrial production;

[0015] 2. The product obtained in Step B1 is an oily substance, which is inconvenient for separation and purification. The reported yield is 67%, and the yield is relatively low;

[0016] 3. In Step B2, the compound (N1,N2-dibenzylethane-1,2-diamine) represented by Chemical Formula 6 is highly toxic and expensive. The reported yield is 54%, and the yield is relatively low, which is not suitable for industrial production. Summary of the Invention

[0017] In order to solve at least one of the above technical problems, the present invention provides an intermediate fragment of an atypical protein kinase C (aPKC) inhibitor compound and a preparation method thereof, and a preparation method of a key intermediate fragment - 2-piperazineacetonitrile, its stereoisomers, tautomers, crystal forms, pharmaceutically acceptable salts, hydrates, solvates or prodrugs obtained by further reacting the intermediate fragment of the aPKC inhibitor compound to form the aPKC inhibitor compound.

[0018] In the first aspect of the present invention, there is provided an intermediate fragment of an aPKC inhibitor compound, which is a compound having the structure of General Formula I, its stereoisomers, tautomers, crystal forms, pharmaceutically acceptable salts, hydrates, solvates or prodrugs,

[0019] General Formula I

[0020] Wherein, R 2 is selected from one or more of Boc, Bn, Cbz, PMB, SEM, Cbz, Ts, Bz, F-moc and Ac, and R 3 is selected from -C(=O)OH, -C(=O)NH2 or -CN.

[0021] In the second aspect of the present invention, there is provided the use of the intermediate fragment of the aPKC inhibitor compound as described above in the preparation of anti-tumor drugs.

[0022] Furthermore, the anti-tumor drug is an atypical protein kinase C inhibitor.

[0023] Furthermore, the aPKC inhibitor is an azaindole inhibitor.

[0024] In a third aspect of the present invention, the present invention also provides a method for preparing an intermediate fragment of an aPKC inhibitor compound as described above, wherein,

[0025]

[0026] It includes the following steps:

[0027] Step C4: Mix the compound represented by chemical formula Cpd-3 with a reaction solvent, add a sodium bicarbonate solution, TEMPO, and a catalyst potassium bromide, add sodium hypochlorite, react, and then quench the reaction with sodium sulfite. Adjust the pH of the reaction solution to 9-12, extract and separate the liquid. Discard the organic phase, adjust the pH of the aqueous phase to 1-4, and crystallize to obtain the compound represented by chemical formula Cpd-4.

[0028] In some embodiments, in the said step C4: Add TEMPO such that the equivalent concentration of TEMPO is 0.1-1.0N.

[0029] In some embodiments, the said step C4 is specifically: Mix the compound represented by chemical formula Cpd-3 with a reaction solvent, add a sodium bicarbonate solution, TEMPO, and a catalyst potassium bromide, dropwise add sodium hypochlorite with the dropping temperature being 0-10°C, react, and the reaction temperature is 0-30°C. Then quench the reaction with sodium sulfite. Adjust the pH of the reaction solution to 9-12, extract and separate the liquid. Discard the organic phase, adjust the pH of the aqueous phase to 1-4, and crystallize at 0-20°C to obtain the compound represented by chemical formula Cpd-4.

[0030] In some embodiments, R 3 is selected from -C(=O)NH2 or -CN;

[0031] Chemical formula Cpd-5

[0032] It further includes the following steps:

[0033] Step C5: React the compound represented by chemical formula Cpd-4 with ethyl chloroformate and / or benzyl chloroformate to form an acid anhydride, and then react the acid anhydride with an amine to form the compound represented by chemical formula Cpd-5.

[0034] In some other embodiments, R 3 is selected from -C(=O)NH2 or -CN;

[0035] Chemical formula Cpd-5

[0036] It further includes the following steps:

[0037] Step C5: The compound represented by chemical formula Cpd-4 is mixed with a reaction solvent, a condensation reagent is added, an ammonia reagent is added, a base is added, and a reaction is carried out. Then, the reaction solution is extracted, the organic phase is taken, and concentrated to obtain the compound represented by chemical formula Cpd-5.

[0038] In some embodiments, in step C5: the condensation reagent is selected from one or more of TBTU, HATU, CDI, EDCI, and HOBt; the ammonia reagent is one or more of ammonium chloride, ammonia water, ammonia methanol, ammonia ethanol, ammonia tetrahydrofuran, and ammonia dioxane solvent; the base is selected from one or more of DIPEA and triethylamine.

[0039] In some embodiments, in step C5: ethyl chloroformate or benzyl chloroformate is used to first synthesize an active ester and then ammonolysis is carried out.

[0040] In some embodiments, R 3 is -CN;

[0041]

[0042] It further includes the following steps:

[0043] Step C6: The compound represented by chemical formula Cpd-5 is mixed with a reaction solvent, a dehydrating reagent is added, and then a base is added, and a reaction is carried out. Then, the reaction solution is extracted, the organic phase is taken, and concentrated to obtain the compound represented by chemical formula Cpd-6.

[0044] In some embodiments, in step C6: the reaction solvent is selected from one or more of toluene, dichloromethane, 2-methyltetrahydrofuran, ethyl acetate, isopropyl acetate, and methyl tert-butyl ether; the dehydrating reagent is selected from one or more of phosphorus oxychloride, phosphorus pentachloride, phosphorus pentoxide, thionyl chloride, TFAA-TEA, and dimethylsulfonium bromide.

[0045] In some embodiments, in step C6: the base is triethylamine.

[0046] In some embodiments, it further includes the following steps:

[0047] Step C1: The compound represented by chemical formula SM1 reacts with the compound represented by chemical formula SM2 to obtain the compound represented by chemical formula Cpd-1;

[0048] Step C2: Under a nitrogen atmosphere, a borane tetrahydrofuran solution is added, the temperature is lowered, the compound represented by chemical formula Cpd-1 is added, the temperature is raised for reaction, and then methanol and an aqueous hydrochloric acid solution are added, and the temperature is raised to carry out decomplexation to obtain the compound represented by chemical formula Cpd-2;

[0049] Step C3: The compound represented by chemical formula Cpd-2 is mixed evenly with a reaction solvent, a base is added, and R2 The protective reagent reacts, and then the reaction solution is adjusted to a pH with an alkali solution, extracted and separated by liquid, and concentrated to obtain a compound represented by the chemical formula Cpd-3;

[0050]

[0051] wherein, R 1 is selected from one or more of methyl, ethyl, propyl and isopropyl.

[0052] In some embodiments, in the step C1: the compound represented by the chemical formula SM1 is dissolved in a reaction solvent, and after mixing evenly, it reacts with the compound represented by the chemical formula SM2; the reaction solvent is selected from one or more of methanol, ethanol, isopropanol, toluene, tetrahydrofuran, and methyltetrahydrofuran.

[0053] In some embodiments, the step C1 is specifically: the compound represented by the chemical formula SM1 (diethyl fumarate) and the reaction solvent are added to a reaction kettle, stirred evenly, the compound represented by the chemical formula SM2 (ethylenediamine) is added dropwise, and stirring is continued for 10-12 h, followed by suction filtration. The filter cake is washed with methyl tert-butyl ether and dried to obtain a compound represented by the chemical formula Cpd-1.

[0054] In some embodiments, in the step C1: the reaction temperature is 20-30 °C, 40-60 °C or 70-90 °C.

[0055] In some embodiments, in the step C2: borane tetrahydrofuran is added such that the equivalent concentration of borane tetrahydrofuran is 3.0-6.0 N.

[0056] In some embodiments, in the step C2: the reaction temperature is 30-70 °C.

[0057] In some embodiments, in the step C2: after heating to decomplex and then cooling to crystallize, filtration is carried out to obtain a compound represented by the chemical formula Cpd-2; the crystallization temperature is 0-20 °C.

[0058] In some embodiments, the reaction solvent in the step C2 is selected from one or more of tetrahydrofuran, 2-methyltetrahydrofuran, and toluene.

[0059] In some embodiments, in the step C3: the R 2 The protective reagent is selected from one or more of Boc anhydride, benzyl chloride, and Cbz-chloride.

[0060] In the fourth aspect of the present invention, there is provided a method for preparing 2-piperazineacetonitrile, its stereoisomers, tautomers, crystal forms, pharmaceutically acceptable salts, hydrates, solvates or prodrugs, including the method for preparing the intermediate fragment of the aPKC inhibitor compound as described above;

[0061] Chemical formula TM-2

[0062] 2-Piperazineacetonitrile is a compound represented by chemical formula TM-2.

[0063] In some embodiments, it includes a method for preparing an intermediate fragment of the aPKC inhibitor compound as described above; it further includes the following steps:

[0064] Step C7: Mix the compound represented by chemical formula Cpd-6 with a reaction solvent, add a deprotection reagent, react, and then filter the reaction solution to obtain 2-piperazineacetonitrile, its stereoisomers, tautomers, crystal forms, pharmaceutically acceptable salts, hydrates, solvates or prodrugs.

[0065] In some embodiments, in step C7: the reaction solvent is ethyl acetate; the deprotection reagent is selected from one or more of palladium-carbon hydrogen gas, piperidine, hydrochloric acid, hydrochloric acid-methanol, hydrochloric acid-ethyl acetate, hydrochloric acid-dioxane, trifluoroacetic acid, sodium hydroxide, potassium hydroxide.

[0066] In some embodiments, the following technical route is adopted:

[0067]

[0068] The pharmaceutically acceptable salts described in the present invention include but are not limited to: salts derived from inorganic acids, such as hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, hydrobromic acid, hydroiodic acid, phosphorous acid; salts derived from organic acids, such as aliphatic monocarboxylic acids, aliphatic dicarboxylic acids, phenyl-substituted alkanoic acids, hydroxyalkanoic acids, alkane diacids, aromatic acids, aliphatic sulfonic acids and aromatic sulfonic acids. Thus, such salts include but are not limited to sulfates, pyrosulfates, bisulfates, sulfites, bisulfites, nitrates, phosphates, monohydrogen phosphates, dihydrogen phosphates, metaphosphates, pyrophosphates, hydrochlorides, bromides, iodides, acetates, octanoates, isobutyrates, oxalates, malonates, succinates, suberates, sebacates, fumarates, maleates, mandelates, benzoates, chlorobenzoates, methylbenzoates, dinitrobenzoates, phthalates, benzenesulfonates, toluenesulfonates, phenylacetates, citrates, lactates, maleates, tartrates and mesylates. See, for example, Berge et al., "Pharmaceutical Salts", J. of Pharmaceutical Science, 1977; 66:1-19. The compounds of the structure shown in general formula I and the compounds represented by chemical formula TM-2 can be prepared into their corresponding pharmaceutically acceptable salts by contacting with a sufficient amount of the required acid to form salts.

[0069] The present invention has the following advantages over the existing technical routes:

[0070] 1. The raw materials, dimethyl fumarate or diethyl fumarate, and ethylenediamine, are all conventional industrial raw materials and are relatively inexpensive;

[0071] 2. In steps C1 to C7, the yield of each step of the reaction is basically between 80% and 95%;

[0072] 3. The post-treatment operation for each step is relatively simple. By crystallization or slurrying and filtration, high-purity intermediates or products (such as 2-piperazineacetonitrile or its pharmaceutically acceptable salts, etc.) can be obtained;

[0073] 4. Reagents such as lithium aluminum hydride, potassium cyanide or sodium cyanide, palladium carbon, allyl cyanide, bromine, and the compound represented by Chemical Formula 6, which are flammable, explosive, highly toxic, and / or expensive, are eliminated. Detailed Embodiments

[0074] In order to make the technical means, creative features, achieved purposes, and effects of the invention easy to understand, the present invention will be further described below in conjunction with specific embodiments. However, the present invention is not limited to the following implemented cases.

[0075] Example 1:

[0076] Synthesis of ethyl 2-(3-oxo-2-piperazinyl)acetate (the compound represented by Chemical Formula Cpd-1, where R 1 is ethyl): In a 50 L reaction kettle, add diethyl fumarate (the compound represented by Chemical Formula SM1, R 1 is ethyl, 2.0 kg), 16 L of isopropanol, stir evenly, control the temperature at 10 ± 5 °C, and drop ethylenediamine (the compound represented by Chemical Formula SM2, 768 g) into the above reaction flask. After dropping, react at 20 - 30 °C for 16 h. Post-treatment: Filter by suction, wash the filter cake with methyl tert-butyl ether (1.0 L), and vacuum-dry the filter cake to constant weight to obtain a white solid, the compound represented by Chemical Formula Cpd-1: (1.80 kg, molar yield: 83.3%), HPLC: 99.72%, MS (m / z, ESI+): 187 M+H.

[0077] 1H NMR (400 MHz, DMSO-d6) δ 7.60 (s, 1H), 4.01 (q, J = 7.1 Hz, 2H), 3.47 (dd, J = 8.0, 4.6 Hz, 1H), 3.20–3.06 (m, 1H), 3.07–2.96 (m, 1H), 2.87 (dt, J = 12.6, 3.8 Hz, 1H), 2.75–2.68 (m, 1H), 2.69–2.62 (m, 1H), 2.55 (s, 1H), 1.14 (t, J = 7.1 Hz, 3H).

[0078] Example 2:

[0079] Synthesis of methyl 2-(3-oxo-2-piperazinyl)acetate (compound represented by chemical formula Cpd-1, R 1 is methyl): In a 50 L reaction kettle, add dimethyl fumarate (compound represented by chemical formula SM1, 2.0 kg) and 16 L of isopropanol, stir evenly, control the temperature at 10 ± 5 °C, and add ethylenediamine (compound represented by chemical formula SM2, R 1 is methyl, 917 g) dropwise to the above reaction flask. After dropping, react at 20 - 30 °C for 16 h. Post-treatment: Concentrate the reaction solution under reduced pressure until solid precipitates, add methyl tert-butyl ether (8.0 L) for pulping, filter by suction, wash the filter cake with methyl tert-butyl ether (1.0 L), and vacuum dry the filter cake to constant weight to obtain a white solid compound represented by chemical formula Cpd-1: (1.97 kg, molar yield: 82.6%), HPLC: 99.53%. MS(m / z,ESI+): 173M+H.

[0080] 1H NMR(400MHz,Methanol-d4)δ3.72–3.68(m,1H),3.67(s,3H),3.37(ddd,J=12.1,10.1,4.5Hz,1H),3.24(dt,J=12.2,3.9Hz,1H),3.11–3.03(m,1H),2.98–2.87(m,1H),2.83(dd,J=16.7,4.2Hz,1H),2.70(dd,J=16.7,7.7Hz,1H).

[0081] Example 3:

[0082] Synthesis of 2-piperazineethanol dihydrochloride (compound represented by chemical formula Cpd-2): After purging with nitrogen in a 50 L reaction kettle, add borane tetrahydrofuran solution (1 mol / L, 26.8 L), cool down to 10 ± 5 °C, and add 2-(3-oxo-2-piperazinyl)ethyl acetate (compound represented by chemical formula Cpd-1, R 1 is ethyl, 1.0 kg) in batches, control the temperature not exceeding 30 °C. After adding, stir at 58 ± 5 °C for 16 h. After the reaction is completed, cool the reaction solution to 10 ± 5 °C, dropwise add methanol (5 L) to quench the reaction. After dropping, stir for 30 min, then start to dropwise add 6M hydrochloric acid (5 L). After dropping, heat up to reflux and stir for 2 h, cool down to 10 ± 5 °C and let it stand overnight, filter by suction, wash the filter cake with acetonitrile (5.0 L) for pulping, filter by suction, and vacuum dry the filter cake to constant weight to obtain a white solid compound represented by chemical formula Cpd-2 (906 g, molar yield: 83.11%), MS(m / z,ESI+): 131,M+H.

[0083] 1H NMR (400 MHz, Deuterium Oxide) δ 3.73–3.55 (m, 5H), 3.40–3.22 (m, 2H), 3.22–3.11 (m, 1H), 1.94–1.70 (m, 2H).

[0084] Example 4:

[0085] Synthesis of 2-ethanol-1,4-bis(tert-butoxycarbonyl)piperazine (compound represented by chemical formula Cpd-3, R 2 is tert-butoxycarbonyl): In a 3.0 L reaction flask, add 2-piperazine ethanol dihydrochloride (compound represented by chemical formula Cpd-2, 400 g), add it to water (2.0 L), stir evenly, adjust the pH to 8 - 9 with saturated sodium carbonate, cool down to 0 - 10 °C, add methanol (1.0 L), add Boc anhydride (859 g). After adding, stir at 25 ± 5 °C for 16 h. After the reaction is completed, concentrate under reduced pressure to remove methanol. The remaining liquid is extracted with methyl tert-butyl ether (3.0 L × 2). The organic phase is washed with water and then dried and concentrated. The residue is slurried with ethyl acetate and n-heptane to obtain a white solid (compound represented by chemical formula Cpd-3, R 2 is tert-butoxycarbonyl, 555 g, molar yield: 85.3%). MS (m / z, ESI+): 131&175, M+H, Boc fragments in the system.

[0086] 1 1H NMR (400 MHz, DMSO-d6) δ 4.50–3.97 (m, 1H), 3.73 (dd, J = 37.0, 12.5 Hz, 2H), 3.46–3.20 (m, 2H), 2.73 (d, J = 60.0 Hz, 2H), 2.46 (p, J = 1.8 Hz, 1H), 1.53 (d, J = 11.5 Hz, 2H), 1.39 (d, J = 28.8 Hz, 18H).

[0087] Example 5:

[0088] 2-ethanol-1,4-bis(tert-butoxycarbonyl)piperazine (compound represented by chemical formula Cpd-3, R 2Synthesis of tert-Butoxycarbonyl): In a 3.0 L reaction flask, add 2-piperazineethanol dihydrochloride (the compound represented by chemical formula Cpd-2, 400 g), add it to THF (4.0 L), stir evenly, add triethylamine (895 g), cool down to 0 - 10 °C, add Boc anhydride (859 g). After adding, stir at 25 ± 5 °C for 16 h. After the reaction is completed, concentrate under reduced pressure to remove the solvent. Add ethyl acetate (3.0 L) to the remaining liquid, extract with water (5.0 L), continue to extract the aqueous phase with ethyl acetate (3.0 L), combine the organic phases, dry and concentrate. Add ethyl acetate and n-heptane to the residue to make a slurry to obtain a white solid, the compound represented by chemical formula Cpd-3 (R 2 is tert-butoxycarbonyl, 561 g, molar yield: 86.2%). MS (m / z, ESI+): 131 & 175, M+H, Boc fragments in the system.

[0089] 1 1H NMR (400 MHz, Methanol-d4) δ 4.23 (s, 1H), 3.93 (d, J = 15.3 Hz, 2H), 3.88–3.77 (m, 1H), 3.63–3.47 (m, 3H), 3.11–2.63 (m, 3H), 1.85–1.58 (m, 3H), 1.44 (s, 18H).

[0090] Example 6:

[0091] 2-Acetyl-1,4-bis(tert-butoxycarbonyl)piperazine (the compound represented by chemical formula Cpd-4, R 2 is tert-butoxycarbonyl) synthesis: In a 3.0 L reaction flask, add 2-ethanol-1,4-bis(tert-butoxycarbonyl)piperazine (the compound represented by chemical formula Cpd-3, R 2 is tert-butoxycarbonyl, 100 g), add it to acetone (800 mL), stir to dissolve, add 5% sodium bicarbonate solution (1.4 L), TEMPO (23.6 g), add potassium bromide (3.6 g), cool down to 0 - 10 °C, dropwise add 10% sodium hypochlorite solution (400 mL). After adding, stir at 15 ± 5 °C for 16 h. After the reaction is completed, add 5% sodium sulfite solution (200 mL), adjust the pH to 2 - 3 with 1N hydrochloric acid, stir and crystallize for 2 - 3 h, filter by suction, and dry the filter cake to obtain a white solid (the compound represented by chemical formula Cpd-4, R 2 is tert-butoxycarbonyl, 89.9 g, molar yield: 86.3%). MS (m / z, ESI+): 145, 189 & 367, M+H, M+Na, Boc fragments in the system.

[0092] 11H NMR (400 MHz, Methanol-d4) δ 4.48 (d, J = 13.0 Hz, 1H), 3.96 (d, J = 12.8 Hz, 2H), 3.83 (d, J = 12.2 Hz, 1H), 3.00 (s, 2H), 2.81 (d, J = 7.3 Hz, 1H), 2.65–2.27 (m, 2H), 1.43 (s, 19H).

[0093] Example 7:

[0094] Synthesis of 2-acetamido-1,4-bis(tert-butoxycarbonyl)piperazine (di-tert-butyl 2-(2-amino-2-oxoethyl)piperazine-1,4-dicarboxylate, the compound represented by Chemical Formula Cpd-5): In a 500 mL reaction flask, 2-acetate-1,4-bis(tert-butoxycarbonyl)piperazine (the compound represented by Chemical Formula Cpd-4, R 2 is tert-butoxycarbonyl, 34.4 g) was added, dissolved in DMF (350 mL), TBTU (35.3 g) and DIPEA (19.3 g) were added. The temperature was lowered to 0 - 10 °C, and a methanol solution of amine (7N, 18 mL) was added dropwise. After the addition was complete, the temperature was raised to 20 ± 5 °C and the reaction was carried out for 2 - 3 h until the reaction was complete. The solvent was removed by concentration under reduced pressure. EA (200 mL) and 5% sodium carbonate solution (350 mL) were added for extraction. The aqueous phase was further extracted with EA (200 mL). The organic phases were combined, washed with 1N hydrochloric acid (300 mL) and saturated brine (300 mL). The organic phase was dried and concentrated until a solid precipitated. n-Heptane (350 mL) was added for slurrying, and the solid was filtered by suction and dried to obtain a white-like product, the compound represented by Chemical Formula Cpd-5 (31.7 g, molar yield: 92.5%). MS (m / z, ESI+): 144, 188 & 366, M+H, M+Na, Boc fragmented in the system.

[0095] 1 1H NMR (400 MHz, DMSO-d6) δ 7.25 (s, 1H), 6.84 (s, 1H), 4.31 (s, 1H), 3.80 (d, J = 16.2 Hz, 2H), 3.69 (d, J = 13.0 Hz, 1H), 2.85 (d, J = 5.8 Hz, 3H), 2.29 (s, 1H), 2.06 (s, 1H), 1.34 (s, 18H).

[0096] Example 8:

[0097] (2-Cyanomethyl)-1,4-bis(tert-butoxycarbonyl)piperazine (di-tert-butyl 2-(cyanomethyl)piperazine-1,4-dicarboxylate, the compound represented by chemical formula Cpd-6) synthesis: In a 500 mL reaction flask, add 2-acetyl-1,4-bis(tert-butoxycarbonyl)piperazine (the compound represented by chemical formula Cpd-6, 34.4 g), add dichloromethane (350 mL), add triethylamine (20.2 g), cool down to 0 - 10 °C, start to dropwise add TFAA (42.0 g). After dropping, warm up to 25 ± 5 °C and react for 12 h until the reaction is complete. Add 5% sodium carbonate solution (200 mL) for extraction. The aqueous phase is further extracted with DCM (100 mL). Combine the organic phases, wash with 1N hydrochloric acid (100 mL) and saturated brine (300 mL). Dry and concentrate the organic phase, add n-heptane (350 mL) for slurrying, filter the solid by suction, and dry to obtain a white-like product, the compound represented by chemical formula Cpd-6 (29.9 g, molar yield: 92.1%). MS (m / z, ESI+): 170&348, M+H, M+Na, Boc fragments in the system.

[0098] 1 H NMR(400MHz,Methanol-d4)δ4.47(s,1H),3.92(dd,J=29.9,12.1Hz,3H),3.05(s,2H),2.78(d,J=45.3Hz,3H),1.46(d,J=3.9Hz,18H).

[0099] Example 9:

[0100] Synthesis of 2-piperazineacetonitrile dihydrochloride (2-(piperazin-2-yl)acetonitrile dihydrochloride, the compound represented by chemical formula TM-1): In a 500 mL reaction flask, add the compound represented by chemical formula Cpd-6 (di-tert-butyl 2-(cyanomethyl)piperazine-1,4-dicarboxylate) (16.3 g), add ethyl acetate (160 mL), cool down to 0 - 10 °C, dropwise add 4N hydrochloric acid ethyl acetate solution (63 mL). After dropping, warm up to 25 ± 5 °C and react for 12 h until the reaction is complete. A large amount of solid precipitates. Add n-heptane (160 mL) for slurrying and filter by suction. Dry the filter cake to obtain a white solid end product, the compound represented by chemical formula TM-1 (8.62 g, molar yield: 87.1%). MS (m / z, ESI+): 126.2, M+H.

[0101] 11H NMR (400 MHz, Deuterium Oxide) δ 3.91 (dtd, J = 12.2, 6.1, 3.3 Hz, 1H), 3.72 (ddd, J = 13.9, 3.3, 1.3 Hz, 1H), 3.69–3.57 (m, 2H), 3.41–3.18 (m, 3H), 3.02 (d, J = 6.2 Hz, 2H).

[0102] Abbreviations:

[0103] For convenience, the following common abbreviations are used in this article (which may not include abbreviations explained earlier and common unit abbreviations such as h, min, N, ml, g, Hz, °C, etc.):

[0104] HPLC represents high performance liquid chromatography

[0105] MS represents mass spectrometry

[0106] NMR represents nuclear magnetic resonance

[0107] Boc represents tert-butoxycarbonyl

[0108] Bn represents benzyl

[0109] Cbz represents benzyloxycarbonyl

[0110] PMB represents p-methoxybenzyl

[0111] SEM represents trimethylsilylethoxymethyl

[0112] Ts represents p-toluenesulfonyl

[0113] Bz represents benzoyl

[0114] F-moc represents fluorenylmethyloxycarbonyl

[0115] Ac represents acetyl

[0116] TBTU represents 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate

[0117] HATU represents N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)uronium hexafluorophosphate

[0118] CDI represents N,N'-carbonyldiimidazole

[0119] EDCI represents 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride

[0120] HOBt represents 1-hydroxybenzotriazole (HOBT)

[0121] TEMPO represents 2,2,6,6-tetramethylpiperidine 1-oxyl

[0122] TFAA-TEA represents trifluoroacetic anhydride-triethylamine

[0123] DMSO represents dimethyl sulfoxide

[0124] DIPEA represents N,N-diisopropylethylamine

[0125] DMF represents N,N-dimethylformamide

[0126] EA represents ethyl acetate.

[0127] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. A method for preparing 2-piperazineacetonitrile hydrochloride, characterized in that, The following technical route is adopted: Among them, R 1 is selected from one or more of methyl, ethyl, propyl, and isopropyl; R 2 is selected from Boc; Step C1: Add the compound represented by chemical formula SM1 and a reaction solvent into a reaction kettle, stir evenly, dropwise add the compound represented by chemical formula SM2, continue stirring for 10 - 12 h, perform suction filtration, wash the filter cake with methyl tert-butyl ether, and dry to obtain the compound represented by chemical formula Cpd-1; the compound represented by SM1 is a diester of fumaric acid, and the compound represented by chemical formula SM2 is ethylenediamine; the reaction solvent is selected from one or more of methanol, ethanol, isopropanol, toluene, tetrahydrofuran, and methyltetrahydrofuran; Step C2: Under a nitrogen atmosphere, add a borane tetrahydrofuran solution, lower the temperature, add the compound represented by chemical formula Cpd-1, raise the temperature for reaction, then add methanol and an aqueous hydrochloric acid solution, raise the temperature to decomplex and obtain the compound represented by chemical formula Cpd-2; Step C3: Mix the compound represented by chemical formula Cpd-2 and a reaction solvent, add a base, add Boc anhydride, react, then adjust the pH of the reaction solution with an alkaline solution, perform extraction and liquid separation, and concentrate to obtain the compound represented by chemical formula Cpd-3; Step C4: Mix the compound represented by chemical formula Cpd-3 and a reaction solvent, add a sodium bicarbonate solution, TEMPO, and a catalyst potassium bromide, add sodium hypochlorite, react, then quench the reaction with sodium sulfite, adjust the pH of the reaction solution to 9 - 12, perform extraction and liquid separation, discard the organic phase, adjust the pH of the aqueous phase to 1 - 4, and crystallize to obtain the compound represented by chemical formula Cpd-4; Step C5: Mix the compound represented by chemical formula Cpd-4 and a reaction solvent, add TBTU, add an ammonia reagent, add DIPEA, react, then extract the reaction solution, take the organic phase, and concentrate to obtain the compound represented by chemical formula Cpd-5; Step C6: Mix the compound represented by chemical formula Cpd-5 and a reaction solvent, add TFAA-TEA, then add a base, react, then extract the reaction solution, take the organic phase, and concentrate to obtain the compound represented by chemical formula Cpd-6; Step C7: Mix the compound represented by chemical formula Cpd-6 and a reaction solvent, add a deprotection reagent, react, then perform suction filtration on the reaction solution to obtain 2-piperazineacetonitrile hydrochloride; the reaction solvent is ethyl acetate; the deprotection reagent is hydrochloric acid ethyl acetate.

2. The preparation method according to claim 1, characterized in that, In step C4: Add TEMPO such that the equivalent concentration of TEMPO is 0.1 - 1.0 N; step C4 is specifically: Mix the compound represented by chemical formula Cpd-3 and a reaction solvent, add a sodium bicarbonate solution, TEMPO, and a catalyst potassium bromide, dropwise add sodium hypochlorite with a dropping temperature of 0 - 10 °C, react at a reaction temperature of 0 - 30 °C, then quench the reaction with sodium sulfite, adjust the pH of the reaction solution to 9 - 12, perform extraction and liquid separation, discard the organic phase, adjust the pH of the aqueous phase to 1 - 4, and crystallize at 0 - 20 °C to obtain the compound represented by chemical formula Cpd-4; In step C5: The ammonia reagent is one or more of ammonium chloride, ammonia water, ammonia methanol, ammonia ethanol, ammonia tetrahydrofuran, and ammonia dioxane solvent; In step C6: The reaction solvent is selected from one or more of toluene, dichloromethane, 2-methyltetrahydrofuran, ethyl acetate, isopropyl acetate, and methyl tert-butyl ether.

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